title: Effect of warfarin anticoagulation on thrombin generation in patients with idiopathic pulmonary arterial hypertension.
abstract: BACKGROUND
  Oral anticoagulant therapy is recommended for patients with pulmonary arterial hypertension (PAH). The rationale for the use of anticoagulant treatment is based on thrombophylic predisposition in PAH and improvement of survival in patients treated with anticoagulation. However, the target INR value has not been evaluated. The aim of this study was to analyze thrombin generation in patients with PAH treated with warfarin anticoagulation.
  
  
  METHODS
  The study was performed in 58 patients with idiopathic PAH treated with warfarin at stable doses. Thrombin generation assay was performed in all subjects and three parameters were derived from the thrombin generation curves: lag time, maximal concentration of formed thrombin (peak thrombin) and area under the curve (AUC). Thrombin generation parameters were correlated with INR and compared between the patient groups with different intensity of anticoagulant therapy.
  
  
  RESULTS
  Significant correlation between the lag time and INR was observed (r = 0.495, p < 0.001). Significant negative correlation between the maximal concentration of formed thrombin and INR and between the area under the curve of thrombin generation and INR was observed (r = -0.709, p < 0.001 and r = -0.784, p < 0.001, respectively). Thrombin generation was significantly reduced in patients with INR between 1.5 and 2.5.
  
  
  CONCLUSIONS
  Low-intensity warfarin anticoagulation with target INR between 1.5 and 2.5 could be effective and sufficient to suppress thrombin generation in patients with idiopathic PAH (Fig. 3, Tab. 4, Ref. 12). Full Text in free PDF www.bmj.sk.
authors.affiliation: 2nd Medical Department-Clinical Department of Cardiology and Angiology of the First Faculty of Medicine and General Teaching Hospital, Prague, Czech Republic. jansapavel@yahoo.com
authors.forename: P
authors.initials: P
authors.lastname: Jansa
authors.forename: I
authors.initials: I
authors.lastname: Hrachovinova
authors.forename: D
authors.initials: D
authors.lastname: Ambroz
authors.forename: J
authors.initials: J
authors.lastname: Maresova
authors.forename: P
authors.initials: P
authors.lastname: Polacek
authors.forename: I
authors.initials: I
authors.lastname: Simkova
authors.forename: A
authors.initials: A
authors.lastname: Linhart
authors.forename: M
authors.initials: M
authors.lastname: Aschermann
mesh_terms: D000925:Anticoagulants / Q000032:analysis*; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000097:blood / Q000188:drug therapy; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D013917:Thrombin / Q000032:analysis*
chemical_list: D000925:Anticoagulants; D013917:Thrombin